Four or five years age I got these two Rimfires at the St Louis Show. I purchased them from a German gentleman. Dispite the US headstamps he said they were of German origin. I don’t remember for sure but I think he said they were Police experimentals.
The first is a 5mm Remington Rimfire Magnum necked down to 17 caliber.
It has an impress “U” headstamp
Case length: 1.013" (25.72mm)
Bullet Dia: .1710" (4.36mm)
Neck Dia:.1895" (4.36mm)
Total weight: 50.88 grains (3.297 grams)
Total Lenght: 1.418" (36.00mm)
The bullet is a jacketed hollow point.
The second is based on a 22 rimfire Magnum Case.
At first I thought it was .17 cal but the bullet diameter is .1755 (4.45mm)
all the 17 cal rimfires and wildcats I known of have .1710 diameter bullets. Could it be a 4.5mm wildcat? It has a Wincherster “Super-X” headstamp.
Case length: 1.063" (26.97mm)
Bullet Dia: .1755" (4.45mm)
Neck diameter: .1960" (4.95mm)
Total Length:1.3855" (35.19mm)
Total weight: 46.48 grains (3.0123 Grams)
The bullet is a pointed full metal jacket. It has an unusual flat squared off tip and a deep groove at the case mouth crimp.
Any information on either of these would be much appreciated.